Contingencies - Additional Information (Details) - Local Tax Assessment - USD ($)	3 Months Ended	12 Months Ended
	Jun. 30, 2016	Dec. 31, 2018
Loss Contingencies [Line Items]
Tax assessment period, beginning date		Jun. 01, 2005
Tax assessment period, ending date		May 31, 2015
Proposed underpaid tax, applicable interest and penalties amount		$ 1,439,452
Local tax assessment, estimated probable loss	$ 391,000